I.

Introduction

Tehrān or Teheran, capital and largest city of Iran, located in the northern part of the country. Tehrān is Iran’s administrative, economic, and cultural center as well as the major industrial and transportation center of the region. The city sits on the slopes of the Elburz Mountains at an elevation of about 1210 m (about 3960 ft), on the northwestern fringes of the Dāsht-e Kavir, a desert in central Iran. The climate has marked seasonal contrasts, with short springs and autumns separating cold winters and hot, dry summers. In July, the average temperature in the southern part of the city is 30° C (86° F), compared with 23° C (73° F) in the higher, northernmost suburbs. In the winter, temperature in the city’s southern areas average 5° C (41° F), and in the northern suburbs, 1° C (34° F). Average annual precipitation is 230 mm (9 in), again with notable differences between the northern suburbs (393 mm/16 in) and the lower southern areas (93 mm/4 in).